A/C Problems (C68)
Thread Starter
Instructor
Joined: Feb 2001
Posts: 243
Likes: 0
From: Los Angeles
A/C Problems (C68)
This nightmare started about 6 weeks ago when my a/c compressor died. When I had the new compressor put in they did the R12 to R134 conversion.
I have the auto climate control (C68), and as long as the car is not moving the a/c works great. If the a/c is on while i'm driving, it surges for a couple of minutes then the compressor kicks off and the light on the climate control starts flashing and sets a DTC09 (low freon). When no leaks were found in the system, I was told that I had a bad control module. I put the new unit in and nothing has changed! :banghead: HELP!! PLEASE!! Am I wrong to think that this is vacuum related? I want to be able to tell these idiots whats wrong.
I don't know if this is related or not but my cruise control won't hold now.
Thanks!
I have the auto climate control (C68), and as long as the car is not moving the a/c works great. If the a/c is on while i'm driving, it surges for a couple of minutes then the compressor kicks off and the light on the climate control starts flashing and sets a DTC09 (low freon). When no leaks were found in the system, I was told that I had a bad control module. I put the new unit in and nothing has changed! :banghead: HELP!! PLEASE!! Am I wrong to think that this is vacuum related? I want to be able to tell these idiots whats wrong.
I don't know if this is related or not but my cruise control won't hold now.
Thanks!
Racer
Joined: Jan 2003
Posts: 321
Likes: 0
From: Birmingham AL
Re: A/C Problems (40th_roadster)
Just a thought and a question to ask an expert.... Does R134 run at different pressures than the R12?? Could be the 134 runs at lower pressures which the control module senses as low freon.
Drifting
Joined: May 2001
Posts: 1,726
Likes: 1
From: COCOA Florida
Re: A/C Problems (40th_roadster)
Just a thought to try...bypass the low pressure switch on the suction line near the firewall by disconnecting the wires and jumpering the terminals. see if the condition continues to surge and set the code. if not, the switch is defective and is a $14.00 item from the parts store...you will not loose any refrigerant as it has a schrader valve under it...just unscrew old, screw on new. hope this helps. Tom
[Modified by C4TOMCAT, 6:53 PM 1/29/2003]
[Modified by C4TOMCAT, 6:53 PM 1/29/2003]
Thread Starter
Instructor
Joined: Feb 2001
Posts: 243
Likes: 0
From: Los Angeles
Re: A/C Problems (C4TOMCAT)
Just a thought to try...bypass the low pressure switch on the suction line near the firewall by disconnecting the wires and jumpering the terminals. see if the condition continues to surge and set the code. if not, the switch is defective and is a $14.00 item from the parts store...you will not loose any refrigerant as it has a schrader valve under it...just unscrew old, screw on new. hope this helps. Tom
Burning Brakes
Joined: Nov 2002
Posts: 807
Likes: 21
From: Los Altos CA
Re: A/C Problems (40th_roadster)
If the refrigerant is low, the low pressure side of the compressor will drop, causing the compressor to shut off. When the pressure rises, the compressor will turn on again. Excessive cycling causes the low freon diagnostic and shuts the compressor off permanently. Since the compressor pulls more on the low pressure side at higher engine rpm's, this would explain the speed dependence - more cycling. However, there is another possible cause other than low freon that will cause excessive low pressure cycling. Did you replace the orifice tube at the evaporator inlet? If the compressor failed, it is likely that the orifice tube screen is plugged with debris. The orifice tube should be replaced whenever a compressor fails.
Melting Slicks
Joined: Jun 2000
Posts: 2,923
Likes: 1
From: Las Vegas NV
Re: A/C Problems (C4TOMCAT)
Just a thought to try...bypass the low pressure switch on the suction line near the firewall by disconnecting the wires and jumpering the terminals. see if the condition continues to surge and set the code. if not, the switch is defective and is a $14.00 item from the parts store...you will not loose any refrigerant as it has a schrader valve under it...just unscrew old, screw on new. hope this helps. Tom
[Modified by C4TOMCAT, 6:53 PM 1/29/2003]
[Modified by C4TOMCAT, 6:53 PM 1/29/2003]
Thanks,
